The system they created now is totally different from the one they had. It’s more efficient by an insane margin. Choice of language seems like it would have trouble breaking the top 5 major reasons.
I migrated Rails apps to Elixir before, we reduced from 15 servers to 3, and 1 was basically "if crap hits the fan", we could have gotten away with 2 easily.
It's worrying that a supposedly high-quality forum like HN receives comments with no substance. If you have an actual counter-argument, let's discuss. If not, well, not an interesting exchange.
It's very hard to provide evidence unless we make a screen-share call where I show you real time dashboards of services being bombarded with thousands of requests per second and for you to see for yourself how the median latency numbers climb from 25ms to 45ms and then fall back to 20-30ms after the burst load subsides.
I find it difficult to just describe this because as much as I've seen it many times in practice, it's also practically impossible (NDAs and compliance nightmares) to demonstrate it to a programmer outside the companies I've worked with without violating all sorts of laws. :(
But yes, basically: a super latency optimized runtime, a GC that's not very sophisticated but it elegantly dodges most GC problems by simply releasing all memory linked to an actor as soon as it quits (and Erlang/Elixir encourage you to spawn many of those in the right conditions; not for every single thing though), and one of the very fastest dynamic languages in the world, probably second only to JS's V8.
All of that is combined with me working with several other programming languages and their hosting solutions which were tripping over themselves when 1000 req/s started coming in (looking at you, Ruby 3.X and Puma and a few other servers; or PHP, or Python).
TL;DR: reliability is much better, latency is predictable.
Weirdest thing is: people don't believe it. If you only knew the CTOs I worked with: they were extremely data-driven and they would not allow me or anyone to just pull all of that out of their bottom. All had to be proven with numbers, and me and my teams did that, many times.
I understand the skepticism somewhat, but you and a few others seem to look at Elixir through the lenses of "too good to be true", and IMO you should try relaxing that skepticism to some extent. And try to be little more sympathetic because again, I literally cannot give you the hard cold data without violating at least three laws.
All I’m saying is that if you can drop 1330 servers just like that, there might be something more going on than Python’s slowness.
This is from experience. I have seen people create slow and fast systems with just about any tech. I can make Elixir crawl, I can assure you of that.
I have seen Python apps use 10 servers and reduced it to one as well. Same tech, just a more efficient mindset. It’s IMO a bit too simplistic to say systems with GCs fall over when under load.
Also nobody used the word "magically" before you did. Note that.
What's your argument exactly? That Elixir is overrated? Or something else?
Furthermore, I am not insisting on my standards of the quality of comments. I am under the impression that's the expected quality of comments on HN at large.
To be clear, I think Elixir is marvelous. This post spiked my interest in it actually. Sorry if I come across ignorant. That’s because I am.
I am not evangelizing tech -- I am a polyglot and I use what I find is best suited for a job, and Elixir happens to cover quite a lot of ground. That's all really. I also use Rust and Golang quite a bit.
I simply get ticked off when people start demeaning something without seriously working with it or even reading a bit beforehand. Sorry if I mistakenly put you in that group.